Surgical instruments which include a tool assembly mounted on a distal end of a body portion of the surgical instrument for articulation are well known. Typically, such surgical instruments include articulation control mechanisms which allow an operator to remotely articulate the tool assembly in relation to the body portion of a surgical instrument to allow the operator to more easily access, operate on, and/or manipulate tissue.
Such articulating tool assemblies have become desirable, especially in the endoscopic surgical procedures. In an endoscopic surgical procedure, the distal end of a surgical instrument is inserted through small incisions in the body to access a surgical site. Typically, a appropriately sized cannula, e.g., 5 mm, 10 mm, etc., is inserted through the body incision to provide a guide channel for accessing the surgical site. Once the distal end of the endoscopic instrument has been received within the body cavity the tool assembly may be articulated.
To activate the tool assembly on the distal end of the surgical instrument in when the tool assembly is in both an articulated and non-articulated position, a drive beam is incorporated into the instrument. The drive beam is generally an elongated flexible member capable of translating lateral movement from the handle assembly to the tool assembly. The flexibility of the drive member permits the tool assembly to be articulated while still maintaining the ability to activate the tool assembly.
The configuration of the flexible drive members makes them susceptible to binding during activation when the tool assembly is in a position other than aligned with the longitudinal axis of the instrument. As the angle between the articulating end and the longitudinal axis approach orthogonal (i.e. 90° from centerline), the likelihood of binding increases. A bound instrument will not function properly and may result in lockout, misfiring, or the like. Furthermore, the limitations imposed by the flexible drive members prevent the articulation joint from being fully articulated to an angle orthogonal to the longitudinal axis formed by the surgical stapler.
Accordingly, it would be desirable to provide a surgical instrument having an articulating tool assembly with an improved drive beam for actuating the tool assembly throughout articulation of the tool assembly.